Magical Girl Lyrical Nanoha A's(魔法少女リリカルなのは A's(エース)Mahō Shōjo Ririkaru Nanoha Ēsu) is a thirteen episode anime that aired between October 1 and December 24, 2005. It is the sequel to Magical Girl Lyrical Nanoha and thus, the second entry in the main Nanoha continuity.

Contents

Six months after the end of Magical Girl Lyrical Nanoha, Fate travels to Midchilda to stand trial, while Nanoha returns to the life of an ordinary girl. One day, however, she is attacked by a mysterious red knight who serves the Book of Darkness: a Lost Logia that must be filled with magic drained from mages' Linker Cores or the spirits of ordinary living beings before it kills its current owner, Hayate Yagami. As old friends reunite to deal with the new threat, they discover the truth behind the Book and its troubled history with the Time-Space Administrative Bureau.

With what happened to Nanoha, the Asura crew has been asigned the mission of stopping the Wolkenritter, and with the Asura being upgraded the captain's team consisting of Admiral Lindy, Chrono, Amy, and Fate move into Nanoha's neighborhood for the time being. At the end of the episode Raising Heart and Bardiche demand a new and dangerous modification to their design.

Signum breaks into the TSAB barrier to help out her teammates with a fight soon following. Nanoha and Fate gain the advantage over their opponents, but a mysterious man arrives to help, and Shamal sacrifices some of the Book of Darkness's pages in order to destroy the barrier and allow the Wolkenritter to escape. It is revealed that the Wolkenritter are programs of the Book of Darkness.

Signum and Shamal recall coming into Hayate's service, and how the love she showed them caused them to develop emotions. While she asked them not to fight, they eventually realized that unless the Book was completed, her life would be endangered, and decided to gather mana for that purpose.

Fate and Nanoha again confront Signum and Vita, trying to get them to reveal their motivations. The mysterious man protects Vita from Nanoha's attack, and then intervenes in Signum's fight with Fate, stealing Fate's Linker Core and incapacitating her.

Hayate's condition worsens, and she is hospitalized after collapsing at home. The TSAB realize that the Book of Darkness is going to kill Hayate upon its completion. Nanoha and Fate visit Hayate in the hospital through Suzuka, a mutual friend.

Chrono continues his research on the Book of Darkness. On Christmas Eve, Nanoha and Fate give Hayate a surprise visit, and encounter the Wolkenritter in the hospital room, learning of their connection to her. The groups fight that night on the hospital roof, but two masked men intervene, incapacitating Nanoha and Fate and draining the Wolkenritter's Linker Cores. Taking on Nanoha and Fate's appearance, they then summon Hayate to the roof and kill Vita in front of her to force her to awaken the Book of Darkness.

Hayate is engulfed by the Book's power. Chrono fights the masked men and discovers that they are the Liese Twins, Admiral Gil Graham's familiars, and that Graham had planned for Hayate to complete the Book of Darkness in order to seal it and her away. While Arisa and Suzuka learn the truth about Nanoha and Fate, Fate gets absorbed by the Book of Darkness.

Although the danger is averted, the potential for the corruption to return remains, and Reinforce gives up her existence in order to prevent that. Hayate and the Wolkenritter join the TSAB, and Nanoha tells her family about what she has been doing as a mage. Six years later, Nanoha, Fate, and Hayate are in middle school, with Hayate having a second Reinforce by her side.